In recent years, an environment where information network can be accessed at any time in any situations, which is referred to as a ubiquitous information society, has been facilitated. In such an environment, an individual identification technique has attracted attentions, such that an identification number (ID) is assigned to each object, whereby the history of the object is clarified and the production, management, or the like is facilitated. Above all, a semiconductor device capable of transmitting and receiving data by wireless communication has begun to be utilized.
As a semiconductor device capable of transmitting, receiving, storing, and deleting data by wireless communication, an individual identification technique utilizing a radio-frequency identification (RFID) tag has attracted attention. The RFID tag is also referred to as an integrated circuit (IC) tag, an RF tag, a wireless tag, an electronic tag, an IC chip, or a wireless chip. A device for reading and writing data (hereinafter referred to as a reader/writer) is used for transmitting and receiving data to and from the RFID tag. The individual identification technique with the use of the RFID tag has been useful for production, management, or the like of an individual object, and application thereof to personal authentication has been expected.
The RFID tag includes an antenna for transmitting and receiving an electromagnetic wave, electric wave, or the like of data by wireless communication, and has a structure in which the antenna and an integrated circuit are formed integrally. Some of the RFID tags generate a DC voltage from an electromagnetic wave, electric wave, or the like transmitted from an external device such as a reader/writer with the use of a rectifier or a rectifier circuit included in the RFID tags. Further, some of the RFID tags are operated with a stable, constant voltage with the use of a controller such as a regulator circuit.